Prosobranchiata \Pros`o*bran`chi*a"ta\, n. pl. [NL., fr. Gr. ?
forward, further + ? a gill.] (Zool.)
The highest division, or subclass, of gastropod mollusks,
including those that have the gills situated anteriorly, or
forward of the heart, and the sexes separate.
[1913 Webster]